This specification relates to modifying the presentation of content items.
The Internet provides access to a wide variety of resources, for example, content items such as video files, audio files, and image files, as well as web pages for particular subjects or articles, any or all of which may be accessible over the Internet. Access to these resources presents opportunities for other content items, such as advertisements or other supplemental content, to be provided with the resources.
Advertising is a primary technique by which providers of products or services communicate with potential purchasers in the hopes of influencing them to purchase the goods or services they are selling. Advertisements may also be used to dispense information, convey a message, or promote a cause. Advertisers generally wish to present advertisements that are likely to attract a viewer's attention, as a viewer is unlikely to be positively influenced by an advertisement that is presented in a format to which the viewer is not receptive.